In the medical profession, the use of catheters to deliver and vent fluids from body vessels is becoming more pervasive due to the advancement of minimally invasive procedures. It is often desired to insert a catheter into a body vessel such as the aorta, urethra etc. via an access vessel having a restricted diameter. The catheter usually has a plurality of lumens, for instance, one lumen to infuse a fluid such as a medicant or oxygenated blood, and another lumen for inflating a balloon to selectively occlude the body vessel. The number of lumens, and particularly the aggregate cross sectional area of the lumens, substantially determines the overall catheter diameter. It is desired to keep the overall diameter of the catheter as small as possible, especially with respect to the access vessel and the vessel for which it is intended to be placed to reduce trauma to the vessel.
With respect to aortic balloon catheters in particular, these catheters may be percutaneously inserted into a patient's femoral artery, serving as an access vessel, and advanced upwardly into the aorta of the patient. According to one conventional method, a first catheter is inserted into the femoral artery and advanced into the ascending aorta. The catheter may include a balloon for selectively occluding the aorta and have multiple lumens terminating at the distal end thereof for delivering cardioplegia to the aortic root and/or venting fluid from the aorta above the aortic root. Other lumens may provide for instrumentation to be inserted into the aorta, which may be advanced through the aortic valve into the heart. The proximal end of the catheter may be provided with a lumen terminating proximate the point of insertion to provide arterial return of oxygenated blood. Alternatively, a separate second catheter may be inserted into the patient's other femoral artery to provide arterial return of oxygenated blood. This second catheter is used to reduce the overall diameter of the first catheter body advanced into the aorta, thus reducing trauma to the aorta lining. The distal end of this second catheter is also advanced only to proximate the point of insertion since it is semi-rigid and has a relatively large diameter to provide the required arterial return of oxygenated blood into the aorta. By using a second catheter, a rather large diameter first catheter is not necessary to be inserted into the aorta which may cause trauma to the lining of the artery. However, returning oxygenated blood well below the aorta requires oxygenated blood to flow counter to typical arterial blood flow, upwardly into the ascending aorta to the various arteries branching therefrom.
The disadvantages of this approach include the fact that returning oxygenated blood to the aorta upwardly in a direction counter to normal flow has been found in some studies to be damaging to the artery lining, and which may create aortic dissection, aneurysms, and in some cases death. In addition, this method requires a second infusion catheter to be inserted and manipulated which can be cumbersome.
A semi-rigid catheter having a large lumen for providing arterial return of oxygenated blood, as well as having lumens for pressure sensing, cardioplegia delivery/venting, and balloon inflation, necessitates a relatively large aortic balloon catheter having a large overall diameter that is difficult to femorally insert and manipulate up into the ascending aorta. If too large a catheter is used, the artery can be damaged or traumatized during insertion. It is desired to provide an improved catheter suited for use in body vessels having a limited diameter while being capable of delivering fluids at a high flow rate, two criteria that typically limit each other. In particular, the improved catheter would have one intended use as a catheter that can be femorally inserted to provide arterial return of oxygenated blood into the ascending aorta.